Earthquake Engineering

Earthquakes are one of the most devastating forces on the planet. The seismic waves that travel through the ground can demolish buildings, kill people, and cost billions of dollars in damage and restoration. According to the National Earthquake Information Center, there are over 20,000 earthquakes every year on average, including 16 major disasters. The damage was caused by the collapse of buildings with people inside, as in previous earthquakes, prompting the development of earthquake-resistant constructions.

Constructions intended to withstand earthquakes are known as earthquake-resistant structures. While no structure can be completely safe from earthquake damage, earthquake-resistant construction aims to build structures that perform better than their conventional equivalents during seismic activity. Building rules state that earthquake-resistant constructions must be able to withstand the greatest earthquake with a reasonable chance of occurring at their site. There are now various design philosophies in earthquake engineering that use experimental results, computer models, and historical earthquake observations to provide the requisite performance for the seismic threat at the location of interest. In this article, we will deal with numerous techniques that can help improve a structure.

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A large number of existing buildings do not have adequate earthquake resistant features as specified as in IS Codes. This is because of some reasons like non availability of competent technical manpower, lack of regulatory mechanisms to check earthquake resistance of proposed constructions and economic constraints.

Earthquake creates great devastations in terms of life, money and failure of structure. It is very important to upgrade certain building systems to make them more resistant to seismic activity. The structures can be earthquake damaged or earthquake vulnerable. Retrofitting proves to be a better economic consideration and immediate shelter to problems rather than replacement of the building. Retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. Retrofitting techniques are also applicable for other natural hazards such as cyclones, tornadoes and wind forces.

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Earthquake causes ground motions in a random fashion, both horizontally and vertically in all directions from the epicenter. As a result, the structures found in the ground vibrate, inducing inertial forces on them. It is therefore essential to ensure stability, strength, and serviceability with acceptable levels of safety by suitable design and detailing.

Due to horizontal shaking of the ground, horizontal inertia forces are generated at the level of the mass of the structure. The lateral inertia forces are transferred by the floor slab to the walls or columns, to the foundations, and finally to the soil. So each of the structural elements like floor slabs, walls, columns, foundations, and connections between them must be designed to safely transfer these inertia forces through them.

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INTRODUCTION
Seismic method of analysis is done in order to ascertain the various responses of buildings during earthquake and also to adopt the retrofitting of structures. It is an important tool for earthquake prone areas like Japan, North-East of India, Nepal, Philippines, and many more. This method of analysis is also important for design of elements of RCC buildings like beam, column, slab which are designed in accordance to IS 13920:2016. The seismic forces are dynamic in nature and these forces are tested for load carrying capacity, ductility, dampness, stiffness and mass. IS 1893:2016 is used to carry out seismic analysis of multi-storeyed building.
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By
Technical paper Presented by:
Mr.Jismon Issac B.E (Mech) A.I.E, MBA

Over the past few years, India has seen a spurt in the vertical growth of buildings. They range from individual houses to very tall skyscrapers. Whenever news on earthquake is reported, we have only one question in our mind – Is our home safe during an earthquake?

Engineers always tell us that earthquake don’t kill, but that will be done by poorly built constructions. Earthquake resistant buildings can be made, only by constructing our homes with ductile character. For a better understanding in earthquake resistant buildings, we must acquire knowledge about earthquakes and its occurrence. The points are given as below;

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